The present invention provides method and apparatus for transmitting packets on a communications ring to overcome the above mentioned problems.
It is, therefore an object of this invention to provide fairness on a buffer insertion ring so that busy nodes on the ring will transmit the same amount of packets in a given time interval.
It is also an object of this invention to provide a communications ring which is deadlock free.
It is also an object of this invention to provide a buffer insertion ring that will operate with multiple control message (SAT's).
Accordingly, the present invention provides a method book for controlling the transmission of packets from the nodes on a communications ring. This invention provides for forwarding a current control message on the ring to indicate to each of the nodes on the ring a first corresponding maximum number of packets that each node is permitted to transmit in a corresponding time interval. This invention also provides for holding a control message by each node until the node holding the control message is satisfied. Satisfaction means that the node has transmitted at least a second (equal or lower than the first) corresponding number of packets or all of the packets that it has to transmit if the number of packets that it has to transmit is less than the second corresponding number. More specifically, the time interval above is the time from when a node receives a current control message to when it forwards a subsequent control message. Again, more specifically, this invention is applied to a buffer insertion ring. With this specific application, each node will transmit packets as long as its insertion buffer contains less than a predetermined number of bits and as long as the node has not transmitted more than its first corresponding maximum number of packets during the above mentioned interval. Also, in this specific application, each node can transmit packets without having to hold any control message.